Chip breaking mechanism for metal drilling and like machines



Jan. 11, 1949. c. B. CLARK 2,458,929

CHIP BREAKING MECHANISM FOR METAL DRILLING AND LIKE MACHINES Filed Dec.28, 1945 Patented Jan. 11, 1949 CHIP BREAKING MECHANISM FOR METALDRILLING AND LIKE MACHINES Carleton B. Clark, Keene, N. H., assignor toKingsbury Machine Tool Corporation, Keene, N. H., a corporation of NewHampshire Application December 28, 1943, Serial No. 515,942

10 Claims. 1

This invention relates to a chip breaking mechanism for employment inmetal drilling and like machines and is more particularly concerned withthe control of the feeding movement of a drill or like metal workingdevice, whereby the tool is caused to perform a progressive, oscillatorymovement during the course of its rotation, wherewith the path of thecutting portion of the tool departs from a uniform helix.

When employed in a metal drilling machine, this departure of the cuttingedge of the tool from a condition of tracing a uniform helix permits theremoval of the metal in the forming of a series of small chips so thatthe same can be removed from the cutting face along the flutes of thedrill without difficulty of clogging or impeding the free movement ofthe tool while doing its work.

The feeding mechanism of such a drilling machine, in accordance with thepresent invention, comprises the structures effective for producing anaxial oscillation between the drill spindle and its support during thecourse of rotation of the spindle; so that when this axial oscillationis superimposed upon the feeding motion of the support itself, awithdrawal movement is produced which is preferably at least equal tothe forward feeding by the primary feeding. means acting upon thespindle support, whereby the cutting edge of the drill bit is caused topass through the surface of the metal being cut and thus producesuccessively a series of separate chips.

In the practice of the invention, this axial oscillation is obtained byproviding a member which rotates about an axis positioned at an anglewith respect to the spindle axis, so thatthe distance between a radialplane of the spindle and a radial plane of this tilted axis varies frompoint to point during the course of revolution of the spindle, wherewitha spindle collar is provided so that a point in its periphery ismaintained at a constant distance from the fixed radial plane throughthe tilted axis and this collar then moves axially with respect to afixed plane through the support axis.

Another feature of the invention is the provision of means for obtainingand maintaining a desired angle of tilt, whereby to determine the extentof the axial oscillations.

In the accompanying drawing is illustrated one form of practicing theinvention in which Figure l is a perspective view of a metal drillingmachine having the present invention therein.-

Figure 2 is an upright sectional view through the spindle and quillassembly of the illustrative metal drilling machine.

Figures 3 and 4 are respectively sectional w'ews substantially on lines3-3 and 4- -4 of Figure 2.

Figure 5 is a perspective view of the adjustin bushing and spacer piece,separated from one another to show their abutting surfaces.

Figure 6 is an unfolded view representing the paths of successivemovements of the two lips of an ordinary metal drill bit through threerevolutions of the spindle.

In these drawings, Figure 1 shows a conventionalized metal drillingmachine having a stand or upright support ID with a drill table Hthereon. The top bracket l2 provides a housing 13 in which the quill l4maybe reciprocated upon rotation of a quill feeding means conventionallyshown as including a gear l5 mounted on a. shaft Hi, this gear l5 beingdriven by a gear l1 which receives power (by means not shown) forproducing a downward feeding motion of the quill l4, and usuallyproducing a retraction thereof automatically at the completion of adrilling operation. Within the quill I4 is a drill spindle l8 which isillustrated as driven by a pulley l9 and a driving belt '20. At thelower end of the drill spindle is a chuck 2| for receiving a drill bit22 which is illustrated as being of the usual twofluted spiral type,with two drilling lips.

As shown in Figure 2, the shaft l6 supports, within the housing l3, aquill gear 25, which engages with the rack teeth 26 on the quill I l.

The lower end of the quill I4 is provided with a housing 30 whose innerwall is substantially cylindrical in the illustratedform. An annularthrust member 3| is located within the housin 30 and has a sphericalsurface for its downwardly directed face. An outer sleeve 32 has itsupper end provided with a spherical surface engaged with thecorresponding surface of the thrust member 3!. This outer sleeve 32receives the outer race 33 of an anti-friction bearing having theballs34 and an inner race 35. An inner sleeve 36 has a radial projectingflange at its lower end for engaging the lower end of the inner race 35,and has a threaded portion, 31 at its upper end to receive a clampingnut 38 which engagesthe upper. end of the inner race 35. Nut lockingmeans 38 are preferably included for holding'the assembly together.

A retaining nut M1 is threadedly engaged with the lower end of thehousing 30 and has an inwardly extending flange for engaging the adjust-.ment bushing 4i which can be rotated within the housing 30. The lowerend of the bushing 4| projects from the nut 45 so that it may be engagedand rotated about the axis of the spindle IS. The upper end of thebushing 4| has a surface 42 which is inclined with regard to the radialplanes through the spindle axis (Fig. 5).

An annular spacer piece 45 bears at its upper end against the lower edgeof the outer sleeve 32, these mating surfaces lying in a plane. The

lower surface of the spacer piece 45 is at an angle to its upper surfaceso that the spacer piece is essentially wedge-shaped (Fig. 5). surfacebears against the upper surface 42 of the bushing 4|. A radial notch 46of limited peripheral dimension is engaged by a pin ll; secured in thehousing 30, wherewith the spacer piece 45' is prevented from rotationwith. respect to the housing 30.

An internal shoulder 48 of the bushing 4| forms an abutment for aresilient structure comprised of two dished spring washers 49-, thisresilient structure bearing at its upper end against the lower edge ofan outer race 58 of the antifriction bearing which has the balls 5| andthe inner race 52. The upper edge of the inner race 52 bears against acollar 53 fixed on the spindle I8.

A thrust transmitting member illustrated as a ball 55'bears againstthecollar 53 at a point offset from the axis of the spindle, and also.bears against the lower surface of theinner sleeve 35. As illustrated,it is preferred to provide a depression 56 in the surface of the innersleeve 36, and an edge notch ST in the collar 53 for receiving this ball55. The ball 55 thus acts to transmit thrust in a direction parallel to.the axis of the spindle l8' and: also serves to deliver tangential forcefrom the collar 53- to the inner sleeve 35' whereby to produce therotation of the latter.

Bydesign of structure, the spherical surfaces of the thrust member 31'and of the outer sleeve 32 have their common center 69 on the axis ofthe spindle l8; and a radial plane of the axis of the inner sleeve 36includes this center 59 and also the center of the ball 55. By thisarrangement, the tilting of the axis of the inner sleeve 36 has noinfluence upon the path of movement of the ball 55 relative to theradial planes of the sleeve 35, but asthe angle of tilt becomes greaterthe distance between fixed radial planes of the spindle and of thistilted axis will" vary, being least at one point and greatest at adiametrically opposite point, along the common axial plane containingboth axes.

The bushing M is preferably formed with an annular hollow boxing 10-which is frictionally fittedv in thebushing and supports a packinggasket H for sealing the interior of the housing.

In operation, while the spindle I8 is rotating about itsaxis, theball-5.51s carried therewith and servesas a driving element for causing.the inner. sleeve35 to rotate within its anti-friction bearing 3335.Upward thrusts along. the. spindle, such. asare produced by reactionfrom thetool engagement with the work, aretransmittedfrom the col-- lar53. through the ball 55, sleeve 35, the anti friction bearing, to theouter sleeve 32 and thence at the spherical surfacesto the thrust member3! and thence to the quill l4.

During the rotation of the inner sleeve 36, however, if the axis of theinner sleeve 35 does not coincide with or lie parallel to the axis ofthe spindlelil, the ball 55 does notmove solely in a plane which isradial to the axis of the spindle l8 and which is fixed relative to-thequill M, with advancement of this radial plane as the q ll This lower isfed downward by the quill gear 25; but during each revolution of thespindle, and assuming no axial movement of the quill, the ball travelsin a circular path in a plane at right angles to the axis of the sleeve36: when the sleeve axis is, as shown, at an angle to the spindle axis,the ball is caused to move relatively upward as it passes from the righthand position shown by a full line into the left hand position shown bya dotted line, under the urgency of the resilient structure 49, and thendown again. This upward and downward movement is occasioned by theangular position of the sleeve 35 relative to the spindle axis, as thedepression is closer to the lower end of the housing 30 at the full-lineposition of the ball 55 than when it is in the dotted line position.Therefore, during the revolution of the spindle, the collar 53..performsupward and downward movements, under the action of the resilientstructure 49 and under the pressure exerted from the rotating innersleeve 55 through the ball 55. In the position of parts shown byfull-lines in Figure 2, the ball 55 Eat the lowest or most forward pointin its translation with the periphery of the inclinable sleeve 35 andhence it is now acting as a thrust-transmitting member to hold thespindle collar 53 at the lowest position, being that in which the ball55 and the collar 53 are closest to the end packing As the spindleturns, owing to the inclined axis of rotation of the sleeve 35, itsdepression or recess 56 moves relatively upwardly in the drawing, oraway from the end packing 75, together with the ball 55, under theaction of springs 49 in this illustrated form, until after degrees ofmovement of the spindle, the ball 55 reaches its greatest distance fromthis packing and therewith the collar 53 has retreated to its greatestdistance from the end packing H. Thereafter, the continued rotation ofthe spindle brings the .ball 55 back again into the position shown inthe drawing, by its motion of transla tion with the spindle and by itsaxial downward movement produced by thrust delivered by the sleeve 35'.-Thus, the ball 55, the collar 53, the spindle and one lip of atwo-lipped drill perform a movement as illustrated by the line 8| inFig-- ure 6; this movement being a composite one consisting of a feedingmotion of the quill and of an axial component of cyclic reciprocation ofthe ball 55. correspondingly, the other lip performs an identicalmovement but at the diametrically opposite part of the hole, that is,180 degrees away, as shown by the line 82 in Fig. 6.

Therefore, in addition to the assumed uniform downward feed ofthe quillthrough the quill feed gear 25, thereis also an axial oscillation whichresults in a successive gouging motion on the part of thedrill bit lips,whereby independent chips are removed from the metal to be drilled.

The path of movement of the two drill lips is represented in Figure 6for the course of three revolutions. Assuming that the upper line 88 ofthis figure "represents the top surface of the piece of work W; thecombined effects of the uniform feed from the gear l1 and of the axialoscillatory feed of the structure shown in Figure 2 causes one of thedrill lips to trace a curve 8| with successive upward and downwardstroke effects while having a constant increment of general downwardmovement. This graph or curve 8| is shown in full lines in Figure 6through three successive revolutions. the drilling operation, this firstdrill lip will follow the curve 8| in the portion of Figure 6representing the first revolution. 180- later, the second At some timeduring the course of lip of the drill will perform the correspondingfull line curve 82. It will thus be noted that the surface at the bottomof the drill hole is not a simple one which may be denominated a conicalspiral, but instead has distortions out of the true conical and the truespiral shapes.

As the first drill lip enters upon its second revolution, represented inthe second panel of Figure 6 by a full line and also represented by thedash line superimposed in the lefthand panelof Figure 6, it will be seenthat this first lip proceeds to follow parallel to its prior course,andiremoves a chip 8% by gouging into the relative elevation left by thesecond lip during its preceding passage, and this chip 83 is rolled upinto a tight conical shape 83a, which will not clog or jamthe drill.

180 later, the second lip performs the movement represented by its fullline curve 82in the middle panel of Figure 6, and also represented bythe dotted line curve 82a in the left hand panel of Figure 6. It will benoted that this lip has been removing a final portion of a chip 84 andcausing it to curl into the shape shown at 84c, and that the second lipcomes relatively out of or above the surface at the bottom of thehole,as provided by the cutting action of the'first lip in removing the chip83, so that the chip 84 is terminated and forms a discrete particle.Substantially 180 later, the second lip, in following the dotted linecurve 82a, again enters the work and cuts out a chip 85.

It will be noted that this successive effect of the lips, in cuttingchips individually from the work, repeats itself so that each lip cutsout one chip during each revolution.

Upon rotation of the bushing 4|, its upper annular surface coacts withthe lower surface of the spacer piece 45, so that this spacer piece iscaused to change the plane of its upper surface and therewith to producea change in the angular position of the outer sleeve 32, by a relativesliding of the spherical surfaces with respect to one'another. Thisadjustment causes a change in the angle of tilt between the axis of theinner sleeve 36 and the axis of the spindle l8; and by regulating thisangle the amount of axial oscillation produced for each revolution ofthe spindle can be varied. As shown in Figure 2, the bushing l4 may havegraduations to indicate the amount of this oscillatory movement. Forexample, with a small drill, the graduation may read in thousandths ofan inch.

The bushing 4! is shown (Figure 2) as having a hole 60 parallel to itsaxis and receiving a spring 6| and a plunger 62 which plunger can engagein one of the series of depressions 63 in the lower surface of thespacer piece 45, wherewith to prevent undesired relative rotations ofthe bushing 4| and of the spacer piece 45, but permitting a relativerotation when adjustment is to be effected. i

As shown in Figure 5, the bushing 4| may have spanner wrench holes 64 ifdesired.

It is obvious that the invention is not limited to the illustrativeform, but may be employed in many ways within the scope of the appendedclaims.

I claim:

1. In metal drilling and like machines, a frame, a support movable onsaid frame and means so to move the same, a drill spindle rotatable insaid support about an axis substantially parallel to such movement, asleeve embracing the spindle axis and rockable to angular positionsrelative to said spindle axis, bearing means on said movable 6, supportfor supporting the sleeve for rotation about its own prevailing axis,and an axial-thrusttransmitting driving element eccentrically mounted onsaid spindle and engaged with said sleeve,

' said element being effective to cause the spindle to drive said sleeveinrotation and also being effective to transmit thrusts between thespindle and sleeve, whereby to produce axial motion of the spindlecompounded of the support and a cyclic movement caused by the angularposition of the sleeve axis relative to the spindle axis.

2. In metal drilling and like machines, a frame, a support movable onsaid frame and means so to move the same, a drill spindle rotatable insaid support, an outer sleeve having a spherical thrust bearing on thesupport, an inner sleeve rotatably carried by a thrust bearing in saidouter sleeve and movable therewith in said spherical bearing so that itsownaxis may be at an angle to the spindle axis, means carried by thesupport and acting upon the said outer sleeve to hold the same againstsaid support and at a predetermined arrgular relation of said axes, athrust and driving element providing a universal pivot connectionbetween the spindle and inner sleeve eccentric to both said axes andeffective to cause the inner sleeve to rotate with the spindle and totransmit axial thrusts between said'sleeve and spindle.

3. In drilling and like machines, a frame, a support movable on saidframe and means so to move the same, a spindle rotatable in saidsupport, an outer sleeve having a spherical thrust bearing on saidsupport, and a bushing reacting against said support and rotatablerelative thereto about the spindle axis and having an inclined endsurface effective for rocking said outer sleeve and for holding the samein rocked position, an inner sleeve carried by a thrust bearing torotate in said outer sleeve, a ball providing a thrust and drivingelement between said spindle and inner sleeve and mounted eccentricallyto both the spindle axis, and movable in a plane containing the centerof said spherical bearing, and means reacting against the bushing formaintaining the ball engaged with the spindle and inner sleeve forcausing the inner sleeve to rotate with the spindle.

4. In drilling and like machines, a frame, a support movable on saidframe and means so to move the same, a spindle rotatable in saidsupport, an outer sleeve having a spherical thrust bearing on saidsupport, an inner sleeve carried by a thrust bearing to rotate in saidouter sleeve, 9, ball providing a thrust and driving element betweensaid spindle and inner sleeve and mounted eccentrically to both thespindle axis and the inner sleeve axis with the center of the ball inthe radial plane throughthe sleeve axis containing the center of saidspherical bearing, means carried by the support and acting upon the saidouter sleeve to hold the same against said support and at apredetermined angular relation of said axes, and spring means for movingthe spindle axially and thereby effective for maintaining engagement ofsaid ball with the spindle and inner sleeve and assuring the rotation ofthe inner sleeve with the spindle.

5. In drilling and like machines, a frame, a support movable on saidframe and means so to move the same, a spindle rotatable in saidsupport, an'outer sleeve having a spherical thrust bearing on saidsupport, an inner sleeve carried by a thrust bearing to rotate in saidouter sleeve, ball providing a thrust and driving element besupport andat a predetermined angular relation:

of said axes, means for maintaining the ball engaged with the spindleand inner sleeve for causing the inner sleeve to rotate with thespindle, and means for holding the outer sleeve in a selected angularposition in saidspherical bearing.

6. In drilling and like: machines having a frame, a quill,

on the quill and providing, aconcave annular spherical thrust surfacearound the spindle, an outer sleeve within the housing and fitting saidspherical surface, an inner sleeve and thrust bearing means supportingthe same in said outer sleeve, said inner sleeve having a depression atone end face, a rotatable bushing held insaid housing and spring-pressedbearing means engaged with the bushing and spindle and permittingrelative axial movementthereof, acollar on the spindle and having avnotch open toward said inner sleeve, a ball engaged in said depressionand said notch for transmitting thrust and rotative forces between theinner sleeve and the spindle, the axes of the spindle and of the innersleeve intersecting at the center for the spherical surface, and meansactuated by the bushing during its rotation relative to the housing forrocking said outer sleeve on said spherical surface.

7. In metal drilling and like machines, a frame, a quill, means forfeeding the quill onthe frame, a drill spindle rotatable in said quilland having a radial extension with a notch, a thrust member and bearingmeans for supporting the member with said member mounted for rotationabout an axis at an angle relative to the axis of said spindle and fortransmitting axial forces from the member to the quill, said memberhaving a depression in its end face opposite said notch, a thrusttransmitting ball located in said notch and depression and travellingabout the spindle axis during the rotation of the spindle and effectiveto cause rotation of the member about its axis, and means effectivetokeep said ball engaged with the surfaces of the notch. and depression.

8. In metal drilling and like machines having a frame, a quill, meansfor feeding the quill, and a drill spindle rotatable in said quill; thecombination therewith of an outer sleeve embracing the spindle axis androckable to angular positions relative to said spindle axis and havingaspherical thrust bearing against the quill to resist drilling pressure,an inner sleeve and bearing means mounted on the outer sleeve forsupporting the inner sleeve for rotation about'its own prevailing axis,said spindle having a collar with an edge notch, said inner sleevehaving a depression in its end adjacent. the collar, a ball engaged inboth said notch and said socket for transmitting end thrust between theinner sleeve and the spindle during drilling and also effective to causethe inner sleeve to rotate with the spindle, means effective during therotation of the spindle for maintaining axial engagement of the ballwith the inner sleeve and the collar, and means for holding the outer;sleeve in a predetermined angular position, whereby the axial movementof the spindle is a composite of the a spindle rotatable in said quill,means for feeding the quill, a housing feeding movement ofthe quill andof the cyclic movement of the ball in its travel during rotation of theinner sleeve.

9. In. metal drilling and like machines having a frame, a quill, meansfor feeding the quill, and a drill spindle rotatable in said quill; thecombination therewith of an outer sleeve embracing the spindle axis androckable to angular positions relative to said spindle axis and havingat one end a spherical thrust bearing against the quill to resistdrilling pressure, an inner sleeve and bearing means mounted on theouter sleeve for supporting the inner sleeve for rotation about its ownprevailing axis, said spindle having a collar with an edge notch, saidinner sleeve having a depression in its end adjacent the collar, a ballengaged in both said notch and said socket for transmitting end thrustbetween the inner sleeve and the spindle during drilling and alsoeffective to cause the inner sleeve to rotate with the spindle, meanseffective during the rotation of the spindle for maintaining, axialengagement of the ball with the inner sleeve and the collar, a ring insaid quill and engaged with the other end of the outer sleeve, means forpreventing rotation of the ring relative to the quill, and a bushinghaving an inclined surface engaged with said ring and being rotatable inthe quill and having an externally accessible partwhereby the bushingmay be rotated, said quill having a thrust bearing for supporting saidbushing against the ring, whereby the axial movement of the spindle is acomposite of the feeding movement of the quill and of the cyclicmovement of the ball in its travel during rotation of the inner sleeve;and

bearing means mounted on the outer sleeve for supporting the innersleeve for rotation about its own prevailing axis, said spindle having acollar with an edge notch, said inner sleeve having a depression in itsend adjacent the collar, a ball engaged in both said notch and saidsocket for transmitting end thrust between the inner sleeve and thespindle during drilling and also effective to cause the inner sleeve torotate with the spindle, means eifective during the rotation of thespindle for maintaining axial engagement of the ball with the innersleeve and the collar, a ring in said quill and engaged with the otherend of the outer sleeve, means for preventing rotation of the ringrelative to the quill, a bushing having an inclined surface engaged withsaid ring and being rotatable in the quill and having an externallyaccessible part whereby the bushing may be rotated, said quill having athrust bearing for supporting said bushing against the ring, said ringhaving a plurality of depressions on its face engaged by the bushing,and a latch carried by the bushing and selectively engageable in one ofsaid ring depressions whereby to hold the bushing in the correspondingrotated position thereof, whereby the axial movement of the spindle is acomposite, of the feeding movement of the quill 2,458,929 10 and of thecyclic movement of the ball in its REFERENCES CITED travel duringrotation of the inner sleeve, and 4 whereby the said cyclic movement isdetermined i g s g ggf gg are of record m the by the angular position ofthe outer sleeve and said angular position of the outer sleeve deter- 5UN TED STATES PATENTS mined by the rotated position of the bushing.Number Name Date 2,252,176 Harris Aug. 12, 1941 CARLETON CLARK 2,328,542Bates l- Sept. '7, 1943

